Imaging array with drive-sense circuits and methods for use therewith

ABSTRACT

An imaging device that generates image data includes: a plurality of pixel sensors arranged in a first direction and a second direction that respond to incident light, wherein the first direction is different than the second direction; A plurality drive-sense circuits, wherein each of the plurality of drive-sense circuits is coupled to a corresponding one of the plurality of pixel sensors and generates a plurality of sensed signals, wherein each of the plurality of drive-sense circuits includes: a first conversion circuit configured to convert a receive signal component of a sensor signal corresponding to the corresponding one of the plurality of pixel sensors into a corresponding one of the plurality of sensed signals; and a second conversion circuit configured to generate, based on the corresponding one of the plurality of sensed signals, a drive signal component of the sensor signal corresponding to the one of the plurality of pixel sensors.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility Patent application claims priority pursuant to35 U.S.C. § 120 as a continuation of U.S. Utility application Ser. No.18/149,807, entitled “IMAGING ARRAY WITH DRIVE-SENSE CIRCUITS ANDMETHODS FOR USE THEREWITH”, filed Jan. 4, 2023, which is a continuationof U.S. Utility application Ser. No. 17/444,951, entitled “IMAGINGDEVICE WITH DRIVE-SENSE CIRCUIT(S) AND METHODS FOR USE THEREWITH”, filedAug. 12, 2021, issued as U.S. Pat. No. 11,575,850 on Feb. 7, 2023, whichclaims priority pursuant to 35 U.S.C. § 119(e) to U.S. ProvisionalApplication No. 63/202,136, entitled “IMAGING DEVICE WITH DRIVE-SENSECIRCUIT(S) AND METHODS FOR USE THEREWITH”, filed May 28, 2021, all ofwhich are hereby incorporated herein by reference in their entirety andmade part of the present U.S. Utility Patent Application for allpurposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable.

BACKGROUND OF THE INVENTION Technical Field of the Invention

This invention relates generally to digital imaging systems and moreparticularly to sensed data collection from imaging sensors.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram illustrating an example of animaging device;

FIG. 2 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s);

FIG. 3 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s);

FIG. 4 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s);

FIG. 5 is a schematic block diagram illustrating an example of a pixelsensor;

FIG. 6 is a schematic block diagram illustrating an example of adrive-sense circuit;

FIG. 7A is a schematic diagram illustrating an example of a pixelsensor;

FIG. 7B is a schematic diagram illustrating an example of a pixelsensor;

FIG. 8 is a graphical diagram illustrating an example of diode voltages;

FIG. 9 is a schematic block diagram illustrating an example of adrive-sense circuit;

FIG. 10 is a flow diagram illustrating an example method;

FIGS. 11 and 12 are schematic diagrams illustrating examples of a pixelsensor;

FIG. 13 is a schematic block diagram illustrating an example of ananalog reference generator;

FIG. 14 is a schematic block diagram illustrating an example of alook-up table;

FIG. 15 is a schematic diagram illustrating an example of a pixelsensor;

FIG. 16 is a flow diagram illustrating an example method;

FIGS. 17A and 17B are schematic diagrams illustrating examples of apixel sensor;

FIG. 18 is a flow diagram illustrating an example method;

FIG. 19 is a schematic block diagram illustrating an example of ananalog reference generator;

FIG. 20A is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s);

FIG. 20B is a graphical diagram illustrating an example diode voltage;

FIG. 21 is a flow diagram illustrating an example method;

FIG. 22 is a timing diagram illustrating an example shutter control;

FIG. 23 is a schematic block diagram illustrating an example of ananalog reference generator;

FIG. 24A is a schematic block diagram illustrating an example of adrive-sense circuit;

FIG. 24B is a schematic block diagram illustrating an example of adrive-sense circuit;

FIG. 25A is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s);

FIG. 25B is a schematic block diagram illustrating an example of ananalog reference generator;

FIG. 26 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s);

FIG. 27 is a flow diagram illustrating an example method;

FIG. 28 is a schematic block diagram illustrating an example of a pixelarray with dark pixels;

FIG. 29 is a schematic block diagram illustrating an example of a pixelarray with dark pixels;

FIG. 30 is a schematic block diagram illustrating an example of a pixelarray with dark pixels;

FIG. 31 is a flow diagram illustrating an example method;

FIG. 32 is a flow diagram illustrating an example method;

FIG. 33 is a flow diagram illustrating an example method;

FIG. 34 is a flow diagram illustrating an example method;

FIG. 35 is a flow diagram illustrating an example method;

FIG. 36 is a flow diagram illustrating an example method;

FIG. 37 is a flow diagram illustrating an example method;

FIG. 38 is a flow diagram illustrating an example method;

FIG. 39 is a schematic block diagram illustrating an example of ahandheld communication device;

FIG. 40 is a schematic block diagram illustrating an example of anelectron microscope;

FIG. 41 is a schematic block diagram illustrating an example of a nightvision device;

FIG. 42 is a schematic block diagram illustrating an example of asatellite imaging device;

FIG. 43 is a schematic block diagram illustrating an example of animaging device;

FIG. 44 is a schematic block diagram illustrating an example of animaging device;

FIG. 45 is a schematic block diagram of a LIDAR device;

FIG. 46 is a schematic block diagram illustrating an example of animaging device;

FIG. 47 is a flow diagram illustrating an example method;

FIG. 48 is a flow diagram illustrating an example method;

FIG. 49 is a flow diagram illustrating an example method;

FIG. 50 is a flow diagram illustrating an example method; and

FIG. 51 is a flow diagram illustrating an example method.

DETAILED DESCRIPTION

FIG. 1 is a schematic block diagram illustrating an example of animaging device 14. In particular, the imaging device 14 can be a digitalvideo camera, a digital still image camera or any other electronicdevice that captures, processes, transmits and/or stores still images orvideo images based on incident light or other radiation, inside oroutside of the optical spectrum.

The imaging device 14 includes a display device 16 such as a touchscreen or other display, an imaging array with one or more drive-sensecircuit(s) 20, a core control module 40, one or more processing modules42, one or more main memories 44, cache memory 46, a graphics processingmodule 48, a display 50, an input-output (I/O) peripheral control module52, one or more input interface modules 56, one or more output interfacemodules 58, one or more network interface modules 60, and one or morememory interface modules 62. A processing module 42 is described ingreater detail at the end of the detailed description and, in analternative example, has a direction connection to the main memory 44.In an alternate example, the core control module and the I/O and/orperipheral control module 52 are one module, such as a chipset, a quickpath interconnect (QPI), and/or an ultra-path interconnect (UPI). Whilean architecture is presented having a particular interconnection scheme,a fewer or greater number of interconnections are likewise possible andfurther one or more buses may likewise be employed.

Each of the main memories 44 includes one or more Random Access Memory(RAM) integrated circuits, or chips. For example, a main memory 44includes four DDR4 (4th generation of double data rate) RAM chips, eachrunning at a rate of 2,400 MHz. In general, the main memory 44 storesdata and operational instructions most relevant for the processingmodule 42. For example, the core control module 40 coordinates thetransfer of data and/or operational instructions from the main memory 44and the memory 64-66. The data and/or operational instructions retrievedfrom memory 64-66 are the data and/or operational instructions requestedby the processing module or will most likely be needed by the processingmodule. When the processing module is done with the data and/oroperational instructions in main memory, the core control module 40coordinates sending updated data to the memory 64-66 for storage.

The memory 64-66 includes one or more hard drives, one or more solidstate memory chips, and/or one or more other large capacity storagedevices that, in comparison to cache memory and main memory devices,is/are relatively inexpensive with respect to cost per amount of datastored. The memories (64, 66, etc.) are coupled to the core controlmodule 40 via the I/O and/or peripheral control module 52 and via one ormore memory interface modules 62. In an example, the I/O and/orperipheral control module 52 includes one or more Peripheral ComponentInterface (PCI) buses or other interfaces to which peripheral componentsconnect to the core control module 40. A memory interface module 62 caninclude a software driver and a hardware connector for coupling a memorydevice to the I/O and/or peripheral control module 52. For example, amemory interface 62 can be in accordance with a Serial AdvancedTechnology Attachment (SATA) port or other memory interface.

The core control module 40 coordinates data communications between theprocessing module(s) 42 and the network(s) 26 via the I/O and/orperipheral control module 52, the network interface module(s) 60, and anetwork card 68 or 70. A network cards (68, 70, etc.) can includewireless communication units and/or a wired communication units. Such awireless communication unit can include a wireless local area network(WLAN) communication device that operates, for example in accordancewith a 802.11 protocol or other wireless local area network protocol, acellular data communication device, a Bluetooth device, a ZigBeecommunication device and/or other wireless communication interface. Sucha wired communication unit can include a Gigabit LAN connection, aFirewire connection, a universal serial bus (USB) interface and/or otherwired interface. The network interface module 60 includes a softwaredriver and a hardware connector for coupling the network card(s) to theI/O and/or peripheral control module 52. For example, the networkinterface module 60 can operate in accordance with one or more versionsof IEEE 802.11, cellular telephone protocols, 10/100/1000 Gigabit LANprotocols, an internet protocol, etc.

The core control module 40 coordinates data communications between theprocessing module(s) 42 and input device(s) 72 via the input interfacemodule(s) 56 and the I/O and/or peripheral control module 52. An inputdevice 72 includes a keypad, a keyboard, control switches, a touchpad, amicrophone, etc. An input interface module 56 includes a software driverand a hardware connector for coupling an input device to the I/O and/orperipheral control module 52. In an example, an input interface module56 is in accordance with one or more Universal Serial Bus (USB)protocols.

The core control module 40 coordinates data communications between theprocessing module(s) 42 and output device(s) 74 via the output interfacemodule(s) 58 and the I/O and/or peripheral control module 52. An outputdevice 74 can include one or more speakers, headphones, earphones orother output device(s). An output interface module 58 can include asoftware driver and a hardware connector for coupling an output deviceto the I/O and/or peripheral control module 52. In an example, an outputinterface module 56 is in accordance with one or more audio codecprotocols.

The imaging array with drive-sense circuit(s) 20 includes an imagingarray with a plurality of pixel sensors coupled to one or more pluralityof drive-sense circuits (DSC). In general, the pixel sensors (e.g., CMOSpixel sensors or other pixel sensors) detect incident light in the formof photons and/or other radiation in a non-optical spectrum. Forexample, when light or other radiation from a scene to be capturedenters the imaging array with drive-sense circuit(s) 20, one or moreelectrical characteristics of the pixel sensors change as a result. Oneor more drive-sense circuits (DSC) coupled to the affected pixel sensorsdetect these changes and generates sensed signals representative ofthese changes to the graphics processing module 48, which may be aseparate processing module or integrated into one or the processingmodule(s) 42.

In various examples, the graphics processing module 48 includes at leastone control signal generator 96 that operates to generate column and rowselection signals for addressing/selecting the individual pixel sensorsof the imaging array to be sensed by one or the drive-sense circuit(s)20 and further that generates one or more other control signals 90 forthe imaging array with drive-sense circuit(s) 20 such as timing signalsfor synchronizing the detection of these changes, resetting the pixelsensors after they are sensed, and/or transfer signals for pixelcircuits with transfer gates, etc. In addition, when video signals areproduced by the graphics processing module 48, the column and rowselection signals (92, 94) and control signals 90 can support theformation of frames of video data. The at least one control signalgenerator 96 can further operate to generate one or more analogreference signals used in the operation of the drive-sense circuits.Further discussion of this feature including several examples will bediscussed in conjunction with the Figures that follow, particularly inconjunction with FIGS. 12-16, 18-19, 21, 23, 24A-B, 27, etc. The controlsignal generator 96 can include, for example: one or more oscillators,clock signal generators and/or other timing generation circuits; a rowdriver, column driver and/or other pixel addressing circuits; one ormore analog reference signal generators; and/or other processingcircuits for generating the various control signal inputs to the imagingarray with drive-sense circuit(s) 20 discussed herein.

The graphics processing module 48 further includes at least onepreprocessing module 98 such as one or more buffers, a frame grabberand/or other processing circuitry that processes sensed signals from thedrive-sense circuits into pixel data such as digital representations ofintensity and/or color, that in conjunction with the correspondingaddresses of the pixel sensors and/or timing, can be used by thegraphics processing module 48 to generate frames of still image dataand/or video data to be displayed by the display device 16, output tothe core control module for storage in a memory 64 or 66, and/or fortransmission via network card 68, 70, etc. While the preprocessingmodule 98 and control signal generator 52 are shown as being a part ofthe graphics processing module 48, either device or both devices couldinstead be implemented as a part of the imaging array with drive-sensecircuit(s) 20 or as part of a separate processing module or modules 42.

Furthermore, the processing module 42 can communicate directly with agraphics processing module 48 to display other data on the display 16.The display 16 can includes an LED (light emitting diode) display, anLCD (liquid crystal display), and/or other type of display technology.The display has a resolution, an aspect ratio, and other features thataffect the quality of the display. The video graphics processing module48 can receive data from the processing module 42, processes the data toproduce rendered data in accordance with the characteristics of thedisplay, and provides the rendered data to the display 16.

Further functions, features, implementations and applications of theimaging array with drive-sense circuit(s) 20 will be discussed inconjunction with the Figures that follow. These functions, features,implementations and applications of the imaging array with drive-sensecircuit(s) 20 can be used in combination or as alternatives. It shouldbe noted that, in various embodiments, the use of one or more drivesense circuits allows the complexity of pixel sensors to be reduced,increasing pixel fill factor and decreasing power consumption,temperature and resulting dark current. Furthermore, the drive sensecircuit(s) can promote the cancellation of spatial noise, dark currentand other undesirable quantities via the use of an analog referencesignal generated based on double sampling, reference pixels, and/or darkpixels, etc.

FIG. 2 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s). In particular, an imagingarray with drive-sense circuit 20-1 is shown in conjunction withgraphics processing module 48. In the example shown, the imaging arraywith drive-sense circuit(s) 20-1 includes a plurality of pixel sensors(PS) 85 that are supported via a single drive-sense circuit 28.

In various examples, the pixel sensors 85 are individually addressableby row select 80 and column select 82 in response to row address signal92 and column address signal 94 generated by the graphics processingmodule 48. Once an individual pixel sensor 85 is addressed, it iscoupled to the drive-sense circuit 28 and a sensed signal 120 isgenerated that indicates, for example, the intensity of the incidentlight on the pixel sensor. After all of the individual pixel sensors 85are addressed, the corresponding set of sensed signals 120 can be usedto generate an entire image or frame of data. This process can berepeated to generate additional images and/or successive frames of videoat a frame rate that set by the graphics processing module 48.Furthermore, the graphics processing module may be configured to addressonly a proper subset of the pixel sensors to generate an image or framewith less than the full resolution of the full array and/or to generateonly a portion of the full image or frame that is possible.

In various examples, the pixel sensors 85 each include a low-powercircuit such as a photo diode and CMOS circuit that operate under thecontrol of one or more control signals 90 generated by the graphicsprocessing module 48. For example, each pixel sensor 85 can beimplemented as a passive pixel sensor, an active pixel sensors (APS)such as a 3T-APS pixel sensor, 4T-APS pixel or other active designs withamplification and/or other pixel designs without amplification that areat least partially driven by the drive-sense circuit 28 and merelyinclude CMOS circuits as switches to control the selection, transfer ofcharge or voltage and/or reset of the photodiode or other lightsensitive element after a sensed signal 120 has been generated.Furthermore, the pixel sensors 85 can be implemented via a CCD pixelsensor and/or other pixel sensor designs.

In operation, the pixel sensors 85 detect incident light in the form ofphotons and/or other radiation in a non-optical spectrum. When light orother radiation from a scene to be captured enters the imaging arraywith drive-sense circuit(s) 20, one or more electrical characteristicsof the pixel sensors 85 change as a result. The drive-sense circuit 28detects these changes and generates sensed signals 120 representative ofthese changes for processing by the preprocessing module 98.

The pixel sensors 85 are oriented in an accordance with the X-Ycoordinate system as shown, where rows are parallel with the X axis andcolumns are parallel with the Y axis. It should be noted however, thatother orientations are possible with rows and columns reversed. Moregenerally, the “rows” correspond to a first direction or trajectory and“columns” correspond to a second direction or trajectory that differsfrom the first direction or trajectory. Furthermore, while these twodirections are shown as being perpendicular, other non-perpendicularimplementations are likewise possible.

In an example of operation, the drive-sense circuit 28 generates thesensed signal 120 corresponding to one of the plurality of pixel sensors85, via a first conversion circuit configured to convert a receivesignal component of a sensor signal 116 corresponding to the one of theplurality of pixel sensors into the sensed signal 120. In particular,the sensed signal 120 indicates a change in an electrical characteristicassociated with the one of the plurality of pixel sensors 85. A secondconversion circuit of the drive-sense circuit 28 is configured togenerate, based on the sensed signal 120, a drive signal component ofthe sensor signal 116 corresponding to the one of the plurality of pixelsensors. This process can be repeated for other pixel sensors 85coupling the drive-sense circuit 28, one-by-one, to individual ones ofthe other pixel sensors 85, to generate a plurality of other sensedsignals 120 corresponding to other ones of the plurality of pixelsensors 85. Image data can then be generated by the graphics processingmodule 48, based on the sensed signal 120 and the plurality of othersensed signals 120.

As previously discussed, the sensed signal 120 is generated thatindicates the intensity of the incident light (or other radiation on thepixel sensor. This can be accomplished by generating the sensed signal120 to indicate a change in one or more electrical characteristics ofthe pixel sensor 85 that by themselves or collectively indicate theintensity of the incident light. The electrical characteristic(s) caninclude a voltage, current, charge, capacitance, reactance, impedance,or other electrical characteristic of the pixel sensor 85.

In various examples, the first conversion circuit is configured toconvert, based on an analog reference signal, the receive signalcomponent of the sensor signal 116 corresponding to the one of theplurality of pixel sensors into the sensed signal 120. The analogreference signal can be generated based on nominal reference data thatindicates a selected electrical characteristic (such as a voltage,current, charge, capacitance, reactance, impedance, or other electricalcharacteristic) of the one of the plurality of pixel sensors 85 in anabsence of the incident light. Furthermore, the nominal reference dataused by the first conversion circuit to generate the sensed signal 120can also be used by the first conversion circuit to generate theplurality of other sensed signals 120 corresponding to the other ones ofthe plurality of pixel sensors 85. Alternatively, the nominal referencedata can be customized to the one of the plurality of pixel sensors 85,and the first conversion circuit can generate the plurality of othersensed signals 120 corresponding to the other ones of the plurality ofpixel sensors 85, based on a plurality of other nominal reference datacustomized to the other ones of the plurality of pixel sensors 85. Inthis fashion, the sensed signal 120 for each pixel sensor 85 can begenerated based on nominal reference data that is selected for that eachpixel sensor 85.

FIG. 3 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s). In particular, an imagingarray with drive-sense circuits 20-2 is shown in conjunction withgraphics processing module 48. Similar elements from FIG. 2 are referredto by common reference numerals. In the example shown, the imaging arraywith drive-sense circuits 20-2 includes a plurality of pixel sensors 85that are supported via an entire row of drive-sense circuits 28.

In operation, row select 80 operates to couple an entire rows of pixelssensors 85 to the drive-sense circuits 28 which generate a correspondingplurality of sensed signals 120, one for each of the pixel sensors 85 inthe row. After all of the rows of pixel sensors 85 are selected, thecorresponding set of sensed signals 120 can be used to generate anentire image or frame of data. This process can be repeated to generateadditional images and/or successive frames of video at a frame rate thatset by the graphics processing module 48. Furthermore, the graphicsprocessing module 48 may be configured to address only a proper subsetof the pixel sensors to generate an image or frame with less than thefull resolution of the full array and/or to generate only a portion ofthe full image or frame that is possible.

In an example of operation, each drive-sense circuit 28 generates thesensed signal 120 corresponding to one of the pixel sensors 85 in aselected row via a first conversion circuit configured to convert areceive signal component of a sensor signal 116 corresponding to the oneof the plurality of pixel sensors into the sensed signal 120. Inparticular, each sensed signal 120 indicates a change in an electricalcharacteristic associated with the one of the plurality of pixel sensorsof the selected row. A second conversion circuit of the drive-sensecircuit 28 is configured to generate, based on the sensed signal 120, adrive signal component of the sensor signal 116 corresponding to the oneof the plurality of pixel sensors in the selected row. This process canbe repeated for other rows pixel sensors 85 by generating, via thedrive-sense circuit 28, a plurality of other sensed signals 120corresponding to other pixel sensors 85 in other rows. Image data canthen be generated by the graphics processing module 48, based on thesensed signal 120 and the plurality of other sensed signals 120.

While the description above has focused on scanning a row of drive-sensecircuits 28 through various rows of pixel sensors 85, in thealternative, a column of drive-sense circuits 28 could be provided thatscans through the various columns of pixel sensors 85.

FIG. 4 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s). In particular, an imagingarray with drive-sense circuits 20-3 is shown in conjunction withgraphics processing module 48. Similar elements from FIG. 2 are referredto by common reference numerals. In the example shown, the imaging arraywith drive-sense circuits 20-3 includes a plurality of pixel sensors(PS) 85′ that are each include a pixel sensor 85 and a dedicateddrive-sense circuit 28 having a first conversion circuit 110 and asecond conversion circuit 112 as shown in conjunction with FIG. 5 .

In various examples, the pixel sensors 85′ are individually addressableby row select 80 and column select 82 in response to row address signal92 and column address signal 94 generated by the graphics processingmodule 48. Once an individual pixel sensor 85′ is addressed, itscorresponding drive-sense circuit 28 generates a corresponding sensedsignal 120 that indicates the intensity and/or color of the incidentlight on the pixel sensor. After all of the individual pixel sensors 85′are addressed, the corresponding set of sensed signals 120 can be usedto generate an entire image or frame of data. This process can berepeated to generate additional images and/or successive frames of videoat a frame rate that set by the graphics processing module 48.Furthermore, the graphics processing module may be configured to addressonly a proper subset of the pixel sensors to generate an image or framewith less than the full resolution of the full array and/or to generateonly a portion of the full image or frame that is possible.

In an example of operation, each drive-sense circuit 28 generates thesensed signal 120 corresponding to one of the pixel sensors 85, via afirst conversion circuit 110 configured to convert a receive signalcomponent of a sensor signal 116 corresponding to the one of theplurality of pixel sensors into the sensed signal 120. In particular,each sensed signal 120 indicates a change in an electricalcharacteristic associated with the corresponding one of the plurality ofpixel sensors 85. The second conversion circuit 112 of the drive-sensecircuit 28 is configured to generate, based on the sensed signal 120, adrive signal component of the sensor signal 116 corresponding to thecorresponding one of the plurality of pixel sensors 85. Image data canthen be generated by the graphics processing module 48, based on thesensed signals 120 for all of the array.

FIG. 6 is a schematic block diagram illustrating an example of adrive-sense circuit. In particular a drive-sense circuit 28 is shownthat includes a first conversion circuit 110 and a second conversioncircuit 112. As previously discussed, the drive-sense circuit 28generates the sensed signal 120 corresponding to one of the pixelsensors 85, via a first conversion circuit 110 configured to convert areceive signal component of the sensor signal 116 of the pixel sensor 85into the sensed signal 120. A second conversion circuit 112 of thedrive-sense circuit 28 is configured to generate, based on the sensedsignal 120, a drive signal component of the sensor signal 116corresponding to the corresponding one of the plurality of pixel sensors85.

The first conversion circuit 110 functions to generate the sensed signal120 to correspond to changes in a receive signal component 118 of thesensor signal 116. For example, the sensed signal 120 indicates a changein an electrical characteristic associated with the pixel sensor 85. Thesecond conversion circuit 112 functions to generate a drive signalcomponent 114 of the sensor signal based on the sensed signal 120 tosubstantially compensate for changes in the receive signal component 118such that, for example, the sensor signal 116 remains substantiallyconstant.

In various examples, the drive signal component 114 of the sensor signal116 can be a voltage or current. The sensed signal 120 can indicate achange in an electrical characteristic associated with the pixel sensor85, such as a voltage, current, charge, capacitance, reactance,impedance, or other electrical characteristic of the pixel sensor 85.

FIG. 7A is a schematic diagram illustrating an example of a pixelsensor. In this example, a passive pixel sensor 85-0 is shown thatincludes a CMOS switch, responsive to row signal 92. The sensor signal116 is coupled to the drive-sense circuit 28, that generates a sensedsignal 120 in response.

In an example of operation, the photodiode is left floating for acertain amount of time, (an integration time), where an electric chargeis generated across the photodiode in response to incident light. At theend of the integration time, the control signal 90-1 closes the CMOSswitch and the charge is then carried off the pixel sensor as sensorsignal 116. The sensor signal 116 has a drive signal component 114generated by the drive-sense circuit 28. A receive signal component ofthe sensor signal 116 is used to generate a sensed signal 120.

This particular configuration requires just one transistor which makesthe pixel sensor design small and easy to implement. The photodiode cantake up more space in relation to the drive-sense circuit28—particularly in circumstances where only a single drive-sense circuit28 or single drive-sense circuit 28 is employed. Therefore, the fillfactor of pixel sensor 85-0 can be larger than the fill factor of otherdesigns with a higher quantum efficiency compared to, for example,active pixel sensors requiring more space for additional CMOS circuitry.In operation, the drive-sense circuit 28 detects changes in one or moreelectrical characteristics of the pixel sensor 85-0, caused by changesin the charge transferred via sensor signal 116.

FIG. 7B is a schematic diagram illustrating an example of a pixelsensor. In this example, a more abstract representation designated pixelsensor 85-1 is shown that includes a switch, responsive to controlsignal 90-1 that can be implemented via a single CMOS transistor.

In an example of operation is shown graphically in FIG. 8 . At someinitial time to, the reset switch is closed, the photodiode is reversebiased and the diode voltage, V_(D), is pinned to the reset voltage. Attime t₁, the reset switch is opened and the diode voltage begins todrop. In particular, the drop in the diode voltage V_(D) beginning attime t₁ can be expressed by the following relationship:

d V _(D) /dt=−I/C _(PD)

where I represents the photodiode current and C_(PD) represents thecapacitance of the photodiode. The photodiode current has two primarycomponents, a dark current I_(D), generated by internal factors of thephotodiode itself and a photo current I_(PH) that is proportional to theincident light on the photodiode. The dark current, for example, can becaused by diffusion, generation recombination currents, tunnelingcurrents, surface leakage current, Frankel-Poole currents, impactionization current and/or other factors and be dependent upon devicetemperature. Considering the nominal case (in the absence of incidentlight),

I _((nominal)) =I _(D)

And

d V _(D(nominal)) /dt=−I _((nominal)) /C _(PD)

In this case, the diode voltage V_(D) falls relatively slowly as shownin FIG. 8 . In the presence of light,

I _((photo)) =I _(D) +I _(PH)

And

d V _(D(photo1)) /dt=−I _((photo)) /C _(PD)

In this case, the diode voltage V_(d) falls more rapidly due to theincreased current as shown in FIG. 8 . Furthermore, the increase innegative slope is proportional to the intensity (amount) of incidentlight on the surface of the photodiode. This change is slope after t₁and/or the difference in diode voltage V_(D) between V_(D(nominal)) andV_(D(photo)) are examples of electrical characteristics that can besensed by drive-sense circuit 28 as sensed signal 120.

FIG. 9 is a schematic block diagram illustrating an example of adrive-sense circuit. The first conversion circuit 110 includes acomparator (comp) and an analog to digital converter (ADC) 130. Thesecond conversion circuit 112 includes a digital to analog converter(DAC) 132, a signal source circuit 133, and a driver.

In an example of operation, the comparator compares the sensor signal116 to an analog reference signal 122 to produce an analog comparisonsignal 124. The inclusion of this analog reference signal 122 allows,for example, the drive-sense circuit 28 to compensate for dark current,fixed biases and/or other nominal operating conditions andcharacteristics that are either common to all of the pixel sensors 85 orcustomized of each of the individual pixel sensors 85. In particular,analog reference signal 122 can be generated based on nominal analogreference data, such as nominal measurements of sensed signal 120 for asingle pixel sensor, a group of pixel sensors, a reference pixel, agroup of reference pixels, etc. Such measurements can be generated, forexample, based on a sampled value of V_(D(nominal)), values ofV_(D(nominal)) over time, a slope of V_(D(nominal)), and/or otherelectrical characteristics of a pixel sensor 85, such as a charge,current, capacitance, reactance, impedance, etc.

The analog to digital converter 130 converts the analog comparisonsignal 124 into the sensed signal 120. The analog to digital converter(ADC) 130 may be implemented in a variety of ways. For example, the(ADC) 130 can include: a flash ADC, a successive approximation ADC, aramp-compare ADC, a Wilkinson ADC, an integrating ADC, a delta encodedADC, and/or a sigma-delta ADC. The digital to analog converter (DAC) 214may be a sigma-delta DAC, a pulse width modulator DAC, a binary weightedDAC, a successive approximation DAC, and/or a thermometer-coded DAC.

The digital to analog converter (DAC) 132 converts the sensed signal 120into an analog feedback signal 126. The signal source circuit 133 (e.g.,a dependent current source, a linear regulator, a DC-DC power supply,etc.) generates a regulated source signal 135 (e.g., a regulated currentsignal or a regulated voltage signal) based on the analog feedbacksignal 126. The driver increases power of the regulated source signal135 to produce the drive signal component 114.

FIG. 10 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-9 . In step 170 an analogreference signal is generated. As previously discussed, an analogreference signal, such as analog reference signal 122 can be generatedbased on nominal analog reference data, such as nominal measurements ofsensed signal 120 for a single pixel sensor, a group of pixel sensors, areference pixel, a group of reference pixels, etc. Such measurements canbe generated, for example, based on a sampled value of V_(D(nominal)),values of V_(D(nominal)) over time, a slope of V_(D(nominal)), and/orother electrical characteristics of one or more pixel sensor 85, such asa charge, current, capacitance, reactance, impedance, etc.

In step 172, the sensed signal is generated, via a drive-sense circuit120 for example, based on a difference from the analog reference signalthat was generated. In step 174, the sensed signal is converted to pixelintensity/color. In step 176, image/frame data is generated by repeatingthis process for some or all of the pixels in the array.

FIG. 11 is a schematic diagram illustrating an example of a pixelsensor. In particular, a pixel sensor 85-2 is shown that is implementedvia a 3T APS circuit having a photodiode and three CMOS transistors. Thephotodiode lies in the photo-sensitive region of the pixel sensor 85.

In operation, the photodiode collects charge proportional to the numberof photons hitting its surface. Each row of pixels is connected to aselect transistor that determines which row of pixels has been selectedfor read out at any one time. Once a row select transistor has beenengaged via row signal 92, the pixel is reset by disabling the resettransistor (which acts as a switch) via control signal 90-1 and thecharge accumulated by the photodiode during a light detection, orintegration, period is buffered by a source follower transistor beforebeing transferred to a column bus connecting each pixel in a singlecolumn. This voltage can be held by a sample-and-hold capacitor of thecolumn bus until it is time for that column bus to be read out or thesample-and-hold capacitor can be omitted with the voltage of sensorsignal 116 being directly converted to the sensor signal 120 via thedrive-sense circuit 28.

Because the 3T pixel is an active pixel sensor (APS), there is anamplifier in each pixel in form of a source follower, which means thetotal area of the pixel that is photo-sensitive is reduced. This lowersthe pixel's fill factor (the percentage of the pixel occupied by thephotodiode and any other unused space) compared to a simpler form ofpassive pixel sensor. An additional problem is that each amplifier willbe slightly different, resulting in spatial offsets, such as fixedpattern noise, throughout the sensor. Fixed pattern noise is morepronounced vertically if additional amplifiers are present in the columncircuitry.

While the use of appropriate analog reference signals 122 by thedrive-sense circuit can help compensate for this noise, given thedrive-sense functionality of the drive-sense circuit 28, the sourcefollower transistor is largely redundant and can be omitted, yielding apassive design with only two transistors that operate as reset and rowselect switches as shown as pixel sensor 85-3 of FIG. 12 . This not onlyincreases the pixel's fill factor, it also helps to reduce the fixedpattern noise of the pixel sensor.

FIG. 13 is a schematic block diagram illustrating an example of ananalog reference generator. In the example shown, an analog referencegenerator 164 generates the analog reference signal 122 in response tonominal analog reference data 160. The analog reference signal generator164 can be included in the drive-sense circuit 28 or provided as aseparate device.

The nominal analog reference data 164 can represent nominal measurementsof sensed signal 120 and/or other nominal electrical characteristics fora single pixel sensor, a group of pixel sensors, a reference pixel, agroup of reference pixels, etc. Such measurements can be generated, forexample, based on a sampled value of V_(D(nominal)), values ofV_(D(nominal)) over time, a slope of V_(D (nominal)), measured values ofsensed signal 120 under nominal conditions (in the absence of light)and/or other electrical characteristics of one or more pixel sensor 85,such as a charge, current, capacitance, reactance, impedance, etc. Invarious examples, the analog reference generator 164 can include asigma-delta DAC, a pulse width modulator DAC, a binary weighted DAC, asuccessive approximation DAC, and/or a thermometer-coded DAC or othercircuit that converts digital to analog signals.

Consider the case where a common set of nominal analog reference data160 is used for all or a group of pixel sensors 85. Nominal measurementstaken for a reference pixel can be stored as nominal analog referencedata 160 and used as a representation of the nominal conditions of thesepixel sensors. Furthermore, nominal measurements taken for a group ofreference pixels or all or a group of the pixel sensors 85 can beaveraged and stored as nominal analog reference data 160 and used as anaverage representation of the nominal conditions of these pixel sensors.In the alternative, nominal measurements taken for each pixel sensor 85can be stored as nominal analog reference data 160 and used as arepresentation of the nominal conditions of each of these correspondingpixel sensors.

FIG. 14 is a schematic block diagram illustrating an example of alook-up table. In particular, look up-table 168 provides nominal analogreference data 166 that is customized for individual pixel sensors 85.The look up-table 168 can be included in the drive-sense circuit 28 orprovided as a separate device.

In operation, nominal measurements taken for each pixel sensor 85 can bestored as nominal analog reference data 160 in the look-up table andindexed, for example by the X-Y coordinates identifying pixel row/columnor other identifying information of each pixel. When a pixel sensorselection signal indicates the identifying information of the pixelsensor in conjunction, for example, with an upcoming sensing of thatpixel sensor by a drive-sense circuit 28, the nominal analog referencedata 160 for that particular pixel sensor 85 can be retrieved for use bythe analog reference generator 164 in generating an analog referencesignal 122 that is customized to that particular pixel.

FIG. 15 is a schematic diagram illustrating an example of a pixelsensor. In particular, a pixel sensor 85-4 similar to pixel sensor 85-3is shown. While a row selection transistor has been omitted, it can beincluded, particularly in circumstances where the pixel sensor isimplemented as part of imaging array with drive-sense circuit 20-1 orimaging array with drive-sense circuits 20-2 presented in conjunctionwith FIGS. 2 and 3 .

In this case the sensed signal 116 is based on V_(D) and consider againthe relationship between V_(D) and I where

d V _(D) /dt=−I _(D) /C _(PD)

In the presence of light, the current I changes this differentialequation from

d V _(D) /dt=−I(I _(D) +I _(PH))/C _(PD)

While, as previously discussed, the detection of changes in the voltageV_(D) by a drive-sense circuit 28 can be used to indicate an amount ofincident light on a pixel sensor, this also indicates that the detectionof changes in current I by a drive-sense circuit can also be used forthis purpose.

Furthermore, this change in current in the presence of incident lightcan also be characterized as a change in capacitance from C_(PD) to anew effective capacitance, C_(eff) of the pixel sensor 85-4 based onnominal dark current I_(D) or

d V _(D) /dt=−I _(D) /C _(eff)

In this case,

−I _(D) /C _(eff)=−(I _(D) +I _(PH))/C _(PD)

Solving for this new effective capacitance, C_(eff) yields

C _(eff) =C _(PD)(I _(D)/(I _(D) +I _(PH)))

Because I_(D) and I_(PH) are both positive quantities, this means thatthe presence of incident light lowers the effective capacitance of thepixel sensor 85 from C_(PD) to C_(eff). This effect can be seen clearlywhen referring back to FIG. 8 since the voltage drops more quickly whenlight is present. Therefore the effect of incident light on the pixelsensor 85 can be measured by the drive-sense circuit 28 a change in theeffective capacitance from C_(PD) to C_(eff) as measured from the sensorsignal 116 by the drive-sense circuit 28 when generating the sensedsignal 120. Furthermore, detecting changes in reactance and/or impedancecaused by the change in capacitance can likewise be effective.

In addition, when the sensed signal 120, for example, indicates theeffective capacitance C_(eff), this quantity can then be preprocessed togenerate the intensity of the incident light because this intensity isproportional to I_(PH). In particular, the nominal values of C_(PD) andI_(D) can be determined either on a common or customized basis fromnominal analog reference data and/or V_(D(nominal)), values ofV_(D(nominal)) over time, a slope of V_(D(nominal)), etc. In this case,

I _(PH) =I _(D)(C _(PD) −C _(eff))/C _(eff)

Therefore, sensing changes in capacitance (and likewise, correspondingchanges in reactance and/or impedance) can be used to indicate anamount/intensity of incident light. When pixel sensors 85 areimplemented with different color filters to generate color images, thecolor information corresponding to each pixel sensor can be used togenerate an amount/intensity of incident light of that correspondingcolor.

In an example of operation, the drive-sense circuit 28 generates asensed signal 120 via a first conversion circuit configured to convert,a receive signal component of a sensor signal 116 of the pixel sensors85 into the sensed signal 120, wherein the sensed signal 120 indicates achange in a capacitance associated with the pixel sensors 85. A secondconversion circuit is configured to generate, based on the sensed signal120, a drive signal component of the sensor signal 116 of the pixelsensors.

In a further example of operation, the drive-sense circuit 28 generatesa sensed signal 120 via a first conversion circuit configured toconvert, a receive signal component of a sensor signal 116 of the pixelsensors 85 into the sensed signal 120, wherein the sensed signal 120indicates a change in a reactance associated with the pixel sensors 85.A second conversion circuit is configured to generate, based on thesensed signal 120, a drive signal component of the sensor signal 116 ofthe pixel sensors.

In another example of operation, the drive-sense circuit 28 generates asensed signal 120 via a first conversion circuit configured to convert,a receive signal component of a sensor signal 116 of the pixel sensors85 into the sensed signal 120, wherein the sensed signal 120 indicates achange in an impedance associated with the pixel sensors 85. A secondconversion circuit is configured to generate, based on the sensed signal120, a drive signal component of the sensor signal 116 of the pixelsensors.

In an additional example of operation, the drive-sense circuit 28generates a sensed signal 120 via a first conversion circuit configuredto convert, a receive signal component of a sensor signal 116 of thepixel sensors 85 into the sensed signal 120, wherein the sensed signal120 indicates a change in a current associated with the pixel sensors85. A second conversion circuit is configured to generate, based on thesensed signal 120, a drive signal component of the sensor signal 116 ofthe pixel sensors.

FIG. 16 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-15 .

In step 150 an analog reference signal is generated. For example, ananalog reference signal, such as analog reference signal 122 can begenerated based on nominal analog reference data that indicates anominal capacitance C_(PD). In step 152, the sensed signal is generated,via a drive-sense circuit 120 for example, based on a change ineffective capacitance of a pixel sensor. In step 154, the sensed signalis converted to pixel intensity/color. In step 156, image/frame data isgenerated by repeating this process for some or all of the pixels in thearray.

FIG. 17A is a schematic diagram illustrating an example of a pixelsensor. In particular, a pixel sensor 85-5 is shown that is implementedvia a 4T APS circuit having a photodiode and four CMOStransistors—including a CMOS switch operating as a transfer gate inresponse to control signal 90-2.

In this example, a pinned photodiode is used with an extra thin p-typeimplant at its surface. When a voltage (called the pinning voltage) isapplied to the diode, two depletion regions form near the back-to-backdiodes. When these two regions meet, the diode is emptied of charge.Since there are no electrons remaining on the diode, the transfer isnoiseless.

In operation, an integration period is completed, followed by theresetting of the separate readout node (known as a floating diffusionnode). This reset value is then sampled before the transfer gate isopened in order to sample the signal value and empty the diode. This isknown as correlated double sampling (CDS) and largely eliminates bothfixed pattern noise and dark current noise because the noise from thefloating diffusion node capacitance is read in both the signal and resetvalue, and thus are eliminated if the two signals are subtracted.

In various examples, the first conversion circuit 110 of the drive-sensecircuit 28 is configured to convert a receive signal component of asensor signal corresponding to the one of the plurality of pixel sensorsinto the sensed signal 120—based on an analog reference signal. In anexample of operation, the analog reference signal is generated based onthe sensed signal 120 generated by the drive-sense circuit 28, prior toenabling the transfer gate. The transfer gate is then enabled and thedrive-sense circuit 28 generates a second sensed signal 120. The use ofthe first sample of the sensed signal (prior to opening the transfergate) to generate such an analog reference serves to compensate forthese undesirable artifacts in the second sensed signal 120.

Again, given the drive-sense functionality of the drive-sense circuit28, the source follower transistor is largely redundant and can beomitted, yielding a passive design with only two transistors thatoperate as reset and row select switches as shown as pixel sensor 85-6of FIG. 17B. This not only increases the pixel's fill factor, it alsohelps to reduce the fixed pattern noise.

FIG. 18 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-17 .

In step 180 an analog reference signal is generated, via a drive-sensecircuit 120 for example, based on a sensed signal before the transfergate is enabled (opened). In step 182, the sensed signal is generatedagain once the transfer gate is opened, via a drive-sense circuit 120for example, based on a difference from the analog reference signal. Instep 184, the sensed signal is converted to pixel intensity/color. Instep 186, image/frame data is generated by repeating this process forsome or all of the pixels in the array.

FIG. 19 is a schematic block diagram illustrating an example of ananalog reference generator. In the example shown, an analog referencegenerator 164′ generates the analog reference signal 122 in response tothe sensed signal 120 (a first sensed signal, e.g. before transfer) froma pixel sensor, such as pixel sensor 85-5 or 85-6 having a transfer gateor other pixel sensor that operates via coordinated double sampling. Theanalog reference signal generator 164′ can be included in thedrive-sense circuit 28 or provided as a separate device.

The analog reference generator 164′ includes a buffer for temporarilystoring the first sample, prior to generation of the analog referencesignal 122 for generation of the second sensed signal 120. In variousexamples, the analog reference generator 164′ can further include asigma-delta DAC, a pulse width modulator DAC, a binary weighted DAC, asuccessive approximation DAC, and/or a thermometer-coded DAC or othercircuit that converts digital to analog signals.

FIG. 20A is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s). In particular, an imagingarray with drive-sense circuit(s) 20-4, shown in schematic crosssection, includes a shutter 202, a lens 204 a color filter array 206 anda pixel array with drive-sense circuits 208. The pixel array withdrive-sense circuit(s) can be implemented via the imaging array withdrive-sense circuit(s) 20-1, 20-2 or 20-3 as previously discussed. Theshutter, when enabled via shutter control 90-3 (e.g. open), passes theincident light through the lens 204 and color filter array 206 to thepixel array with drive-sense circuit(s) 208 and when not enabled viashutter control 90-3 (disabled, e.g. shut), blocks the incident light.

The lens 204 can be implemented via a monolithic resin lens, an array ofmicro-lenses or other lens that directs the incident light through thecolor filter array to the pixels of the pixel array with drive-sensecircuit(s) 208. The color filter array 206 provides color filterseparation to direct light of different colors to differing pixelsensors. In various examples, the color filter array 206 and pixel arraywith drive-sense circuit(s) 208 are configured in a Bayer pattern wherefour adjacent pixels have two green (G) pixels, one red (R) pixel andone blue (B) pixel, however, other color patterns with other colors suchas emerald (E), cyan (C), yellow (Y), White (W), in patterns such asRGBE, RYYB, CYYM, CYGM, RGBW, X-Trans, RCCC, RCCB, etc. can likewise beimplemented.

The shutter 202 can be implemented via an electromechanical shutter orelectronic shutter such as a focal-plane shutter, leaf shutter, rotatingshutter, diaphragm shutter, LCD shutter, rolling shutter or othershutter or shutter equivalent. The shutter 202 can be used in differentways. Referring back to FIG. 8 , the shutter control can be synchronizedwith the reset control signal 90-1 and closed except during the times t,where

t ₁ <t<t ₂

In this fashion, the generation of I_(PH) is coordinated with thesensing/integration period between t₁<t<tor a sampling time t₂ used bythe drive-sense circuit 28—depending on the implementation.

In another example, the shutter 202 can be used to support another formof double sampling. In particular, nominal analog reference data 160 forsome or all of the pixel sensors 85 or 85′ can be generated based onfirst sensed signals 120 when the shutter 202 is not enabled (shut).These nominal analog reference data 160 can be used to generate analogreference signal for the drive-sense circuit(s) 28 when generatingsecond sensed signals 120 when the shutter 202 is enabled (open).

FIG. 20B is a graphical diagram illustrating an example diode voltage.In particular, a diode voltage V_(D) is shown as a function of timecorresponding to a pixel sensor 85. At some initial time to, the resetswitch and shutter 202 are both closed, the photodiode is reverse biasedand the diode voltage, V_(D), is pinned to the reset voltage. At timet₁, the reset switch is opened while the shutter 202 remains closed. Thediode voltage begins to drop but the shutter is or remains closed. Inparticular, the drop in the diode voltage V_(D(nominal)) beginning attime t₁ can be expressed by the following relationship:

d V _(D) /dt=−I _(D) /C _(PD)

where I represents the photodiode current and C_(PD) represents thecapacitance of the photodiode. A first sensed signal 120 generatedduring this period can be used to generate the nominal analog referencedata for the pixel sensor, and in particular gives and indication of theactual dark current and/or nominal photodiode capacitance of thisparticular pixel sensor (in the absence of incident light).

At time t₂, the reset switch is closed and the diode voltage is againpinned to the reset voltage which is achieved at t₃, at which point thereset switch and shutter are both opened. In this case, the diodevoltage V_(D) falls more rapidly in the presence of incident light, dueto the increased current, increase in negative voltage slope anddecreased effective capacitance. These can be sensed by drive-sensecircuit 28 that uses the nominal analog reference data to generate acorresponding nominal analog reference signal. This helps compensatesfor the dark current of this particular pixel sensor 85 in generatingthe second sensed signal 120.

FIG. 21 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-20 . Step 210 includes generatingan analog reference signal based on a sensed signal generated by thedrive-sense circuit with the shutter closed. Step 212 includes resettingthe pixel sensor and generating, via the drive-sense circuit, anothersensed signal based on the analog reference signal when the shutter isopen. In step 214, the sensed signal is converted to pixelintensity/color. In step 216, image/frame data is generated by repeatingthis process for some or all of the pixels in the array.

FIG. 22 is a timing diagram illustrating an example shutter control. Inthe example shown, shutter control 90-3 toggles between closed an openfor the entire array. When the shutter is closed, nominal analogreference (NAR) data are generated for some or all of the pixel sensors85 or 85′ based on first sensed signals 120 from the drive-sensecircuit(s) 28. When the shutter is open, second sensed signals 120 aregenerated by the drive-sense circuit(s) 28 for some or all of the pixelsensors 85 or 85′.

In various embodiments, the number of shutter open periods in a secondof time corresponds to a video frame rate to be generated such as 1.5FPS, 5 FPS, 10 FPS, 15 FPS, 20 FPS, FPS, 60 FPS, 120 FPS, or otherhigher or lower rate, etc. It should be noted that, while a timingdiagram shown that alternates between open and closed conditions, inother examples, NAR data can be generated less frequently, only once atdevice start-up or via some other pattern.

FIG. 23 is a schematic block diagram illustrating an example of ananalog reference generator. In the example shown, an analog referencegenerator 164′ generates the analog reference signal 122 in response tothe sensed signal 120 (a first sensed signal, e.g. with the shutterclosed) from a pixel sensor 85 or 85′. The analog reference signalgenerator 164′ can be included in the drive-sense circuit 28 or providedas a separate device.

The analog reference generator 164′ includes a buffer for temporarilystoring the first sample, prior to generation of the analog referencesignal 122 for generation of the second sensed signal 120. In variousexamples, the analog reference generator 164′ can further include asigma-delta DAC, a pulse width modulator DAC, a binary weighted DAC, asuccessive approximation DAC, and/or a thermometer-coded DAC or othercircuit that converts digital to analog signals.

FIGS. 24A and 24B are schematic block diagrams 28-3 illustrating anexample of a drive-sense circuit. In particular, the drive-sense circuit28-3 has many similar elements the drive-sense circuit 28-2 of FIG. 9 tothe that are referred to by common reference numerals.

In the example shown, the second conversion circuit 112 can beselectively enabled and disabled. Furthermore an implementation ofdouble sampling is presented. FIG. 24A represents a time period wherethe shutter is closed. An analog reference signal 122 is set to zero orsome other nominal DC offset. The second conversion circuit 112 isdisabled and the sensed signal 120 (shutter closed) is generated as thedifference between the sensor signal 116 and analog reference signal122—and therefore is a representation of V_(D(nominal)) with or withoutthe nominal DC offset, and consequently indicative of I_(D) and/orC_(PD).

The sensed signal 120 (shutter closed) can be stored as nominal analogreference data that is used by analog reference generator 164′ togenerate an analog reference signal 122 during a later time periodrepresented FIG. 24B. In this case, the second conversion circuit 112 isenabled to support the generation of sensed signal 120 (with the shutteropen).

FIG. 25A is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s). Similar elements to theimaging array of FIG. 20A are represented by common reference numerals.In this case, however, the shutter 202 is omitted and a color filterlayer with photomasks 222 is included forming a photo array with darkpixels 220.

The photomasks can be constructed of a metallic patches or other opaqueportions that block incident light from reaching the surface of the darkpixels. These dark pixels can operate as reference pixels and can beconstructed to mimic the functionality of the remaining pixel sensors 85or 85′ of the pixel array. When sensed by a drive-sense circuit 28, thedark pixels are used to generate sensed signals 120 representative ofthe nominal operation in the absence of incident light. Thisconfiguration supports dark current compensation in the drive-sensecircuit via analog reference signals generated via sensed signals 120from these dark pixels.

In an example of operation, nominal analog reference data for some orall of the (non-dark) pixel sensors 85 or 85′, such as nominal analogreference data 160, can be generated by a drive-sense circuit 28 basedon sensed signals 120 generated for these dark pixels. Similarly, thedrive-sense circuit 28-3 configuration of FIG. 24B can be employed thatoperates based on a zero or nominal DC offset as the analog referencesignal and with the second conversion circuit disabled. In otherconfigurations, a drive-sense circuit 28-2 configuration of FIG. 9 canbe employed. These nominal analog reference data 160 can be used togenerate analog reference signals 122 for the drive-sense circuit(s) 28when generating second sensed signals 120 when the shutter 202 isenabled (open).

FIG. 25B is a schematic block diagram illustrating an example of ananalog reference generator. In the example shown, an analog referencegenerator 164′ generates the analog reference signal 122 in response tothe sensed signal 120 from the pixel sensor 85 or 85′ of a dark pixel.The analog reference signal generator 164′ can be included in thedrive-sense circuit 28 or provided as a separate device.

The analog reference generator 164′ includes a buffer or other memoryfor storing the sensed signal 120 corresponding to the dark pixel(s) asnominal analog reference data, prior to generation of the analogreference signal 122. In various examples, the analog referencegenerator 164′ can further include a sigma-delta DAC, a pulse widthmodulator DAC, a binary weighted DAC, a successive approximation DAC,and/or a thermometer-coded DAC or other circuit that converts digital toanalog signals.

Consider the case where a common set of nominal analog reference data160 is used for all or a group of pixel sensors 85 or 85′ of the pixelarray with dark pixel(s). Nominal measurements, such as sensed signal120, taken for a dark pixel can be stored as nominal analog referencedata 160 and used as a representation of the nominal conditions for eachof these pixel sensors. Furthermore, nominal measurements taken for agroup of dark pixels can be averaged and stored as nominal analogreference data 160 and used as a representation of the nominalconditions for all or a group of these pixel sensors. In thealternative, nominal measurements taken for a particular dark pixel canbe stored as nominal analog reference data 160 and used as arepresentation of the nominal conditions of only a single pixel sensor85 or 85′ immediately adjacent to the dark pixel or only a small groupof immediately adjacent pixel sensors 85 or 85′. As used herein, animmediately adjacent pixel sensor means having a physical proximity suchthat there are no other pixel sensors physically between the dark pixeland the immediately adjacent pixels sensor.

FIG. 26 is a schematic block diagram illustrating an example of animaging array with drive-sense circuit(s). In particular, a portion of aschematic cross section of an imaging array with drive-sense circuit(s)of FIG. 25A is shown. Incident light is guided by the lens array 204through corresponding color filters 230 to corresponding live pixelssensors 85 (non-dark pixels). Conversely, photomasks 232 block theincident light from reaching the pixel sensors 85″ (dark pixels). Whileshown as pixel sensors 85 and pixel sensors 85″ coupled to a one or moredrive-sense circuit(s) 28, pixel sensors 85′ could likewise be employedfor either dark or non-dark pixels.

FIG. 27 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-26 . Step 250 includes generatingan analog reference signal based on a sensed signal generated by thedrive-sense circuit for a dark pixel. Step 252 includes resetting thepixel sensor and generating, via the drive-sense circuit, another sensedsignal based on the analog reference signal. In step 254, the sensedsignal is converted to pixel intensity/color. In step 256, image/framedata is generated by repeating this process for some or all of thepixels in the array.

FIG. 28 is a schematic block diagram illustrating an example of a pixelarray with dark pixels. In particular, a pixel array with dark pixels220-1 is shown having a sub-array of (live) pixels 85 or 85′ and asub-array of dark pixels 85 or 85′. Placing columns/rows of dark pixelsbetween rows of live pixels have the advantage to reduce spatialvariations in manufacturing and/or spatial variations of pixeltemperature that have an effect on dark current. Presumably, sensedsignals 120 for adjacent dark pixels, alone or averaged based onmultiple adjacent dark pixels, provide the most accurateprediction/approximation of nominal electrical characteristics of thelive pixels adjacent to them.

FIG. 29 is a schematic block diagram illustrating an example of a pixelarray with dark pixels. In particular, a pixel array with dark pixels220-2 is shown having a sub-array of (live) pixels 85 or 85′ and asub-array of dark pixels 85 or 85′. Placing the dark pixels only alongthe periphery of the array increases the live-to-dark ratio and supportshigher resolution for arrays of the same size.

FIG. 30 is a schematic block diagram illustrating an example of a pixelarray with dark pixels. In particular, a group of 4 pixels in a pixelarray with dark pixels 220-3 is shown. The group has 3 (live) pixelsensors 85 or 85′, each responding to a different color (e.g, red, greenand blue) and a single of dark pixel 85 or 85′. In this configuration,nominal analog reference data for the dark pixel is used to generateanalog reference signals 122 for each of the three live pixels in thegroup.

FIG. 31 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-31 . Step 700 includes providing aplurality of pixel sensors that respond to incident light. Step 702includes coupling a drive-sense circuit to one of the plurality of pixelsensors in response to a row selection signal and a column selectionsignal.

Step 704 includes generating a sensed signal via the drive-sensecircuit, wherein the drive-sense circuit includes: a first conversioncircuit configured to convert a receive signal component of a sensorsignal corresponding to the one of the plurality of pixel sensors intothe sensed signal; and a second conversion circuit configured togenerate, based on the sensed signal, a drive signal component of thesensor signal corresponding to the one of the plurality of pixelsensors. Step 706 includes generating a plurality of other sensedsignals corresponding to other ones of the plurality of pixel sensors byperforming steps 702 and 704 for the other ones of the plurality ofpixel sensors. Step 708 includes generating image data based on thesensed signal and the plurality of other sensed signals.

FIG. 32 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-31 . Step 720 includes providing aplurality of pixel sensors arranged in a first direction and a seconddirection that respond to incident light, wherein the first direction isdifferent than the second direction. Step 722 includes coupling, inresponse to subset selection signal, a plurality of drive-sense circuitsto a selected subset of the plurality of pixel sensors along the firstdirection. Step 724 includes generating a plurality of sensed signalsvia the plurality of drive-sense circuits, wherein each of the pluralityof drive-sense circuits includes: a first conversion circuit configuredto convert a receive signal component of a sensor signal correspondingto one of the plurality of pixel sensors in the selected subset, into acorresponding one of the plurality of sensed signals; and a secondconversion circuit configured to generate, based on the correspondingone of the plurality of sensed signals, a drive signal component of thesensor signal corresponding to the one of the plurality of pixel sensorsin the selected subset. Step 726 includes generating a plurality ofother sensed signals corresponding to other subsets of the plurality ofpixel sensors in the first direction by performing steps 722 and 724 forthe other subsets of the plurality of pixel sensors. Step 728 includesgenerating image data based on the plurality of sensed signals and theplurality of other sensed signals.

FIG. 33 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-32 . Step 740 includes providing aplurality of pixel sensors arranged in a first direction and a seconddirection that respond to incident light, wherein the first direction isdifferent than the second direction. Step 742 includes providing aplurality drive-sense circuits, wherein each of the plurality ofdrive-sense circuits is coupled to a corresponding one of the pluralityof pixel sensors.

Step 744 includes generating a plurality of sensed signals via theplurality of drive-sense circuits, wherein each of the plurality ofdrive-sense circuits includes: a first conversion circuit configured toconvert a receive signal component of a sensor signal corresponding tothe corresponding one of the plurality of pixel sensors into acorresponding one of the plurality of sensed signals; and a secondconversion circuit configured to generate, based on the correspondingone of the plurality of sensed signals, a drive signal component of thesensor signal corresponding to the one of the plurality of pixelsensors. Step 746 includes generating image data based on the pluralityof sensed signals.

FIG. 34 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-33 . Step 760 includes providing aplurality of pixel sensors that respond to incident light. Step 762includes providing at least one drive-sense circuit.

Step 764 generating a sensed signal via the at least one drive-sensecircuit corresponding to one of the plurality of pixel sensors, whereinthe at least one drive-sense circuit includes: a first conversioncircuit configured to convert, based on an analog reference signal, areceive signal component of a sensor signal corresponding to the one ofthe plurality of pixel sensors into the sensed signal, wherein theanalog reference signal is generated based on nominal reference datathat indicates pixel sensor performance in absence of the incidentlight; and a second conversion circuit configured to generate, based onthe sensed signal, a drive signal component of the sensor signalcorresponding to the one of the plurality of pixel sensors. Step 766includes generating a plurality of other sensed signals corresponding toother ones of the plurality of pixel sensors by performing step 764 forthe other ones of the plurality of pixel sensors. Step 768 includesgenerating image data based on the sensed signal and the plurality ofother sensed signals.

FIG. 35 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-34 . Step 780 includes providing aplurality of pixel sensors that respond to incident light. Step 782includes providing at least one drive-sense circuit.

Step 784 includes generating a sensed signal via the at least onedrive-sense circuit corresponding to one of the plurality of pixelsensors, wherein the at least one drive-sense circuit includes: a firstconversion circuit configured to convert, a receive signal component ofa sensor signal corresponding to the one of the plurality of pixelsensors into the sensed signal, wherein the sensed signal indicates achange in a capacitance associated with the one of the plurality ofpixel sensors; and a second conversion circuit configured to generate,based on the sensed signal, a drive signal component of the sensorsignal corresponding to the one of the plurality of pixel sensors. Step786 includes generating, via the at least one drive-sense circuit, aplurality of other sensed signals corresponding to other ones of theplurality of pixel sensors; and Step 788 includes generating image databased on the sensed signal and the plurality of other sensed signals.

In various examples, the plurality of pixel sensors each include a CMOScircuit having a photodiode. The first conversion circuit can beconfigured to convert, based on an analog reference signal, the receivesignal component of the sensor signal corresponding to the one of theplurality of pixel sensors into the sensed signal, wherein the analogreference signal is generated based on nominal reference data thatindicates an electrical characteristic of the one of the plurality ofpixel sensors in an absence of the incident light. The nominal referencedata used by the first conversion circuit to generate the sensed signalcan also be used by the first conversion circuit to generate theplurality of other sensed signals corresponding to the other ones of theplurality of pixel sensors. The nominal reference data can be customizedto the one of the plurality of pixel sensors and further the firstconversion circuit can generate the plurality of other sensed signalscorresponding to the other ones of the plurality of pixel sensors, basedon a plurality of other nominal reference data customized to the otherones of the plurality of pixel sensors. The electrical characteristiccan indicate a capacitance of the one of the plurality of pixel sensorsin an absence of the incident light.

In various examples, the at least one drive-sense circuit includes asingle drive-sense circuit that is selectively coupled to the one of theplurality of pixel sensors to generate the sensed signal and isselectively coupled to each of the other ones of the plurality of pixelsensors to generate the plurality of other sensed signals. The at leastone drive-sense circuit can include a plurality of drive-sense circuitsthat is coupled to a selected subset of the plurality of pixel sensorsalong a first direction. The at least one drive-sense circuit caninclude a plurality of drive-sense circuits each coupled to acorresponding one of the plurality of pixel sensors.

FIG. 36 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-35 . Step 800 includes providing aplurality of pixel sensors that respond to incident light. Step 802includes providing at least one drive-sense circuit. Step 804 includesgenerating an analog reference signal corresponding to one of theplurality of pixel sensors, prior to enabling the transfer gate. Step806 includes enabling the transfer gate. Step 808 includes generating asensed signal via the at least one drive-sense circuit corresponding tothe one of the plurality of pixel sensors, wherein the at least onedrive-sense circuit includes: a first conversion circuit configured toconvert, based on the analog reference signal, a receive signalcomponent of a sensor signal corresponding to the one of the pluralityof pixel sensors into the sensed signal; and a second conversion circuitconfigured to generate, based on the sensed signal, a drive signalcomponent of the sensor signal corresponding to the one of the pluralityof pixel sensors.

Step 810 includes generating a plurality of other sensed signalscorresponding to other ones of the plurality of pixel sensors byperforming steps 804, 806 and 808 for the other ones of the plurality ofpixel sensors. Step 812 includes generating image data based on thesensed signal and the plurality of other sensed signals.

FIG. 37 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-36 . Step 820 includes providing aplurality of pixel sensors that respond to incident light. Step 822includes providing at least one drive-sense circuit. Step 824 includesproviding a shutter that, when enabled, passes the incident light andwhen not enabled, blocks the incident light. Step 826 includesgenerating at least one analog reference signal corresponding to one ofthe plurality of pixel sensors, when the shutter is not enabled.

Step 828 includes generating a sensed signal via the at least onedrive-sense circuit corresponding to the one of the plurality of pixelsensors when the shutter is enabled, wherein the at least onedrive-sense circuit includes: a first conversion circuit configured toconvert, based on the at least one analog reference signal, a receivesignal component of a sensor signal corresponding to the one of theplurality of pixel sensors into the sensed signal; and a secondconversion circuit configured to generate, based on the sensed signal, adrive signal component of the sensor signal corresponding to the one ofthe plurality of pixel sensors. Step 830 includes generating a pluralityof other sensed signals corresponding to other ones of the plurality ofpixel sensors by performing step 828 for the other ones of the pluralityof pixel sensors. Step 832 includes generating image data based on thesensed signal and the plurality of other sensed signals.

FIG. 38 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-37 . Step 840 includes providing aplurality of pixel sensors that respond to incident light. Step 842includes providing at least one drive-sense circuit. Step 844 includesproviding at least one dark pixel that does not respond to the incidentlight. Step 846 includes generating at least one analog reference signalvia the at least one dark pixel.

Step 848 includes generating a sensed signal corresponding to one of theplurality of pixel sensors via the at least one drive-sense circuit,wherein the at least one drive-sense circuit includes: a firstconversion circuit configured to convert, based on the at least oneanalog reference signal, a receive signal component of a sensor signalcorresponding to the one of the plurality of pixel sensors into thesensed signal; and a second conversion circuit configured to generate,based on the sensed signal, a drive signal component of the sensorsignal corresponding to the one of the plurality of pixel sensors. Step850 includes generating a plurality of other sensed signalscorresponding to other ones of the plurality of pixel sensors byperforming step 848 for the other ones of the plurality of pixelsensors. Step 852 includes generating image data based on the sensedsignal and the plurality of other sensed signals.

FIG. 39 is a schematic block diagram illustrating an example of ahandheld communication device. In particular, a handheld communicationdevice 1014 is shown that includes one or more similar elements toimaging device 14 that are referred to by common reference numerals. Invarious embodiments, the handheld communication device 1014 can beimplemented as a tablet, laptop computer, smartphone, smartwatch, smartdisplay device, or other portable personal communication device.

The handheld communication device 1014 includes one or more imagingarray with drive-sense circuit(s) 20 that facilitates the capture offrames of still and/or video data. The handheld communication device1014 further includes a one or more wireless interfaces (72, 74) forsending and receiving data via wireless communications. The one or morewireless interfaces (72, 74) can include 802.11 transceivers, 4G or 5Gtransceivers, Bluetooth transceivers, Zigbee transceivers or otherwireless interface devices that allow the handheld communication device1014 to send and receive text and chat messages, email message, voicecalls, engage in social media messaging, share audio, video, stillimages and/or other media. Furthermore, the display device 16 canprovide a touch screen interface as a user interactive input/outputdevice that allows the user to, for example, facilitate the capture offrames of still and/or video data, to store the still and/or video data,to append text, graphics, audio and/or other media to the still and/orvideo data, to upload or share the still and/or video data, to sendmessages that contain the still and/or video data, and/or to facilitatethe other operations of the handheld communications device.

In an example of operation, the handheld communications device 14operates to perform operations that include:

-   -   providing a plurality of pixel sensors that respond to incident        light;    -   providing at least one drive-sense circuit;    -   generating, a sensed signal via the at least one drive-sense        circuit corresponding to one of the plurality of pixel sensors,        wherein the at least one drive-sense circuit includes: a first        conversion circuit configured to convert, a receive signal        component of a sensor signal corresponding to the one of the        plurality of pixel sensors into the sensed signal, wherein the        sensed signal indicates a change in an electrical characteristic        associated with the one of the plurality of pixel sensors; and a        second conversion circuit configured to generate, based on the        sensed signal, a drive signal component of the sensor signal        corresponding to the one of the plurality of pixel sensors.    -   generating a plurality of other sensed signals corresponding to        other ones of the plurality of pixel sensors via the at least        one drive-sense circuit; and    -   generating image data based on the sensed signal and the        plurality of other sensed signals for display via a touch        screen.

FIG. 40 is a schematic block diagram illustrating an example of anelectron microscope. In particular, an electron microscope is presentedthat includes an electron gun 1100, one or more lenses 1102, a specimenholder 1104 and an imaging device 14 that responds to incidentelectrons.

In operation, the electron gun generates an electron beam 1120. The oneor more lenses 1102 form the electron beam 1120 into a primary electronbeam 1122 that is focused on a specimen to be imaged. The specimenholder 1104 holds the specimen. In various examples, the specimen holder1104 can include a vacuum chamber that reduces the amount of airmolecules surrounding the specimen that might be impacted by the primaryelectron beam, thereby reducing undesirable noise in the resultantimage. The secondary electron beam 1124 results from transmission of theprimary electron beam 1122 through the specimen (when implemented in atransmission electron microscope configuration) or reflection of theprimary electron beam 1122 from the specimen (when implemented in areflection electron microscope configuration).

In various examples, the imaging device 14 operates by:

-   -   providing a plurality of pixel sensors that respond to an        incident electron beam;    -   providing at least one drive-sense circuit;    -   generating, a sensed signal via the at least one drive-sense        circuit corresponding to one of the plurality of pixel sensors,        wherein the at least one drive-sense circuit includes: a first        conversion circuit configured to convert, a receive signal        component of a sensor signal corresponding to the one of the        plurality of pixel sensors into the sensed signal, wherein the        sensed signal indicates a change in an electrical characteristic        associated with the one of the plurality of pixel sensors; and a        second conversion circuit configured to generate, based on the        sensed signal, a drive signal component of the sensor signal        corresponding to the one of the plurality of pixel sensors;    -   generating a plurality of other sensed signals corresponding to        other ones of the plurality of pixel sensors via the at least        one drive-sense circuit; and    -   generating image data based on the sensed signal and the        plurality of other sensed signals.

FIG. 41 is a schematic block diagram illustrating an example of a nightvision device. The night vision device 1214 includes one or more lenses1202 and an imaging device 14, 1244-1 or 1244-2. In various examples,the night vision device 1214 can be implemented as a night visioncamera, a night vision scope, a telescope, night vision goggles, orother low light or night vision imaging capture device. In operation,primary incident light 1220 from a scene 1204 is formed into secondaryincident light 1222 focused on the surface of the imaging device 14,1244-1 or 1244-2. The primary incident light 1220 can be an incident lowlight signal that comes from the scene 1204 itself and/or can bereflected from a light source 1206 included in the night vision device1214.

In an example of operation, the imaging device 14, 1244-1 or 1244-2operates by:

-   -   providing a plurality of pixel sensors that respond to an        incident low light signal;    -   providing at least one drive-sense circuit;    -   generating, a sensed signal via the at least one drive-sense        circuit corresponding to one of the plurality of pixel sensors,        wherein the at least one drive-sense circuit includes: a first        conversion circuit configured to convert, a receive signal        component of a sensor signal corresponding to the one of the        plurality of pixel sensors into the sensed signal, wherein the        sensed signal indicates a change in an electrical characteristic        associated with the one of the plurality of pixel sensors; and a        second conversion circuit configured to generate, based on the        sensed signal, a drive signal component of the sensor signal        corresponding to the one of the plurality of pixel sensors;    -   generating a plurality of other sensed signals corresponding to        other ones of the plurality of pixel sensors via the at least        one drive-sense circuit; and    -   generating image data based on the sensed signal and the        plurality of other sensed signals.

FIG. 42 is a schematic block diagram illustrating an example of asatellite imaging device. The satellite imaging device 1234 includes oneor more lenses 1202 and an imaging device 1244-2. In operation, primaryincident light 1220 from a scene 1204 is formed into secondary incidentlight 1222 focused on the surface of the imaging device 1244-2.

In an example of operation, the imaging device 1244-2 operates by:

-   -   providing a plurality of pixel sensors that respond to incident        light;    -   providing at least one drive-sense circuit;    -   generating, a sensed signal via the at least one drive-sense        circuit corresponding to one of the plurality of pixel sensors,        wherein the at least one drive-sense circuit includes: a first        conversion circuit configured to convert, a receive signal        component of a sensor signal corresponding to the one of the        plurality of pixel sensors into the sensed signal, wherein the        sensed signal indicates a change in an electrical characteristic        associated with the one of the plurality of pixel sensors; and a        second conversion circuit configured to generate, based on the        sensed signal, a drive signal component of the sensor signal        corresponding to the one of the plurality of pixel sensors;    -   generating a plurality of other sensed signals corresponding to        other ones of the plurality of pixel sensors via the at least        one drive-sense circuit;    -   generating image data based on the sensed signal and the        plurality of other sensed signals; and    -   transmitting the image data to a ground-based receiver via a        wireless interface.

FIG. 43 is a schematic block diagram illustrating an example of animaging device. In particular, an imaging device 1244-1 is shown thatincludes similar elements to imaging device 14 that are referred to bycommon reference numerals. In various implementations, the image data ismerely generated and displayed by the display device 16. In theseexamples, the image data may not be stored and the memory interfacemodule(s) 62, separate memories 64 and 66 may be omitted, in lieu ofdedicated memories provided in conjunction with one or more othermodules, as may be required. Furthermore, the image data may not betransmitted and the network interface module(s) 60, separate networkcards 68 and 68 may be omitted, if not required.

FIG. 44 is a schematic block diagram illustrating an example of animaging device. In particular, an imaging device 1244-2 is shown thatincludes similar elements to imaging device 14 that are referred to bycommon reference numerals. In various implementations, the image data ismerely generated and transmitted via network card 68 or 70. In theseexamples, the image data may not be stored and the memory interfacemodule(s) 62, separate memories 64 and 66 may be omitted, in lieu ofdedicated memories provided in conjunction with one or more othermodules, as may be required. Furthermore, the image data may or may notbe displayed and the I/O interface module 54 and display device 16 maybe omitted, if not required.

FIG. 45 is a schematic block diagram of a LIDAR device. The LIDAR device1214, for example of an autonomous vehicle, includes a controllablemirror and an imaging device 1344. The light source 1306 can beimplemented via a semiconductor laser, other laser or other source ofcoherent light that is represented by generated light 1312.

In operation, the generated light 1312 is reflected from thecontrollable mirror as reflected light 1314. The controllable mirror1310 controls the reflected light 1314 so as to scan the scene 1304 andgenerate, via reflection from the scene, primary incident light 1320.The primary incident light 1320 is reflected back via the controllablemirror as secondary incident light 1322 that is incident to the surfaceof the imaging device 1344.

In an example of operation, the imaging device 1344 operates by:

-   -   providing at least one pixel sensor that responds to incident        laser light;    -   providing at least one drive-sense circuit coupled to the at        least one pixel sensor;    -   generating, a sensed signal via the at least one drive-sense        circuit, wherein the at least one drive-sense circuit includes:        a first conversion circuit configured to convert, a receive        signal component of a sensor signal corresponding to the at        least one pixel sensor into the sensed signal, wherein the        sensed signal indicates a change in an electrical characteristic        associated with the one of the plurality of pixel sensors; and a        second conversion circuit configured to generate, based on the        sensed signal, a drive signal component of the sensor signal        corresponding to the at least one pixel sensor;    -   generating image data based on the sensed signal; and    -   transmitting the image data to an autonomous vehicle system of        the autonomous vehicle.

In this fashion the autonomous vehicle system can use the image data forpurposes of vehicle control, navigation and/or other purposes.

FIG. 46 is a schematic block diagram illustrating an example of animaging device. In particular, an imaging device 1344 is shown thatincludes similar elements to imaging device 14 that are referred to bycommon reference numerals.

In the example shown, the controllable mirror 1310 scans the scene undercontrol of control signals 90 from the graphics processing module, theimage data is merely generated and transmitted via network card 68 or70. In this example, the image data may not be displayed and the I/Ointerface module 54, and display device 16 may be omitted, if notrequired. As shown, network card 68 is employed to communicate with anautonomous vehicle system, for example, to transmit the image data. Inaddition, the wireless interface 72 can communicate with an autonomousvehicle server, to receive updates, transmit image data, error reports,and/or other data.

FIG. 47 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-46 . Step 1400 includes providinga plurality of pixel sensors that respond to incident light. Step 1402includes providing at least one drive-sense circuit.

Step 1404 includes generating, a sensed signal via the at least onedrive-sense circuit corresponding to one of the plurality of pixelsensors, wherein the at least one drive-sense circuit includes: a firstconversion circuit configured to convert, a receive signal component ofa sensor signal corresponding to the one of the plurality of pixelsensors into the sensed signal, wherein the sensed signal indicates achange in an electrical characteristic associated with the one of theplurality of pixel sensors; and a second conversion circuit configuredto generate, based on the sensed signal, a drive signal component of thesensor signal corresponding to the one of the plurality of pixelsensors. Step 1406 includes generating a plurality of other sensedsignals corresponding to other ones of the plurality of pixel sensorsvia the at least one drive-sense circuit. Step 1408 includes generatingimage data based on the sensed signal and the plurality of other sensedsignals.

In various examples, the plurality of pixel sensors each include a CMOScircuit having a photodiode. The first conversion circuit can beconfigured to convert, based on an analog reference signal, the receivesignal component of the sensor signal corresponding to the one of theplurality of pixel sensors into the sensed signal, wherein the analogreference signal is generated based on nominal reference data thatindicates an electrical characteristic of the one of the plurality ofpixel sensors in an absence of the incident light. The nominal referencedata used by the first conversion circuit to generate the sensed signalcan also be used by the first conversion circuit to generate theplurality of other sensed signals corresponding to the other ones of theplurality of pixel sensors. The nominal reference data can be customizedto the one of the plurality of pixel sensors and further the firstconversion circuit can generate the plurality of other sensed signalscorresponding to the other ones of the plurality of pixel sensors, basedon a plurality of other nominal reference data customized to the otherones of the plurality of pixel sensors. The electrical characteristiccan indicate a capacitance of the one of the plurality of pixel sensors.

In various examples, the at least one drive-sense circuit includes asingle drive-sense circuit that is selectively coupled to the one of theplurality of pixel sensors to generate the sensed signal and isselectively coupled to each of the other ones of the plurality of pixelsensors to generate the plurality of other sensed signals. The at leastone drive-sense circuit can include a plurality of drive-sense circuitsthat is coupled to a selected subset of the plurality of pixel sensorsalong a first direction. The at least one drive-sense circuit caninclude a plurality of drive-sense circuits each coupled to acorresponding one of the plurality of pixel sensors.

FIG. 48 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-47 . Step 1420 includes providinga plurality of pixel sensors that respond to an incident electron beam.Step 1422 includes providing at least one drive-sense circuit.

Step 1424 includes generating, a sensed signal via the at least onedrive-sense circuit corresponding to one of the plurality of pixelsensors, wherein the at least one drive-sense circuit includes: a firstconversion circuit configured to convert, a receive signal component ofa sensor signal corresponding to the one of the plurality of pixelsensors into the sensed signal, wherein the sensed signal indicates achange in an electrical characteristic associated with the one of theplurality of pixel sensors; and a second conversion circuit configuredto generate, based on the sensed signal, a drive signal component of thesensor signal corresponding to the one of the plurality of pixelsensors. Step 1426 includes generating a plurality of other sensedsignals corresponding to other ones of the plurality of pixel sensorsvia the at least one drive-sense circuit. Step 1428 includes generatingimage data based on the sensed signal and the plurality of other sensedsignals.

FIG. 49 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-48 . Step 1440 includes providinga plurality of pixel sensors that respond to an incident low lightsignal. Step 1442 includes providing at least one drive-sense circuit.

Step 1444 includes generating, a sensed signal via the at least onedrive-sense circuit corresponding to one of the plurality of pixelsensors, wherein the at least one drive-sense circuit includes: a firstconversion circuit configured to convert, a receive signal component ofa sensor signal corresponding to the one of the plurality of pixelsensors into the sensed signal, wherein the sensed signal indicates achange in an electrical characteristic associated with the one of theplurality of pixel sensors; and a second conversion circuit configuredto generate, based on the sensed signal, a drive signal component of thesensor signal corresponding to the one of the plurality of pixelsensors. Step 1446 includes generating a plurality of other sensedsignals corresponding to other ones of the plurality of pixel sensorsvia the at least one drive-sense circuit. Step 1448 includes generatingimage data based on the sensed signal and the plurality of other sensedsignals.

FIG. 50 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-49 . Step 1460 includes providinga plurality of pixel sensors that respond to incident light. Step 1462includes providing at least one drive-sense circuit.

Step 1464 includes generating, a sensed signal via the at least onedrive-sense circuit corresponding to one of the plurality of pixelsensors, wherein the at least one drive-sense circuit includes: a firstconversion circuit configured to convert, a receive signal component ofa sensor signal corresponding to the one of the plurality of pixelsensors into the sensed signal, wherein the sensed signal indicates achange in an electrical characteristic associated with the one of theplurality of pixel sensors; and a second conversion circuit configuredto generate, based on the sensed signal, a drive signal component of thesensor signal corresponding to the one of the plurality of pixelsensors.

Step 1466 includes generating a plurality of other sensed signalscorresponding to other ones of the plurality of pixel sensors via the atleast one drive-sense circuit. Step 1468 includes generating image databased on the sensed signal and the plurality of other sensed signals.Step 1470 includes transmitting the image data to a ground-basedreceiver via a wireless interface.

FIG. 51 is a flow diagram illustrating an example method. In particular,a method is presented for use with one or more functions/featuresdescribed in conjunction with FIGS. 1-50 . Step 1480 includes providingat least one pixel sensor that responds to incident laser light. Step1482 includes providing at least one drive-sense circuit coupled to theat least one pixel sensor.

Step 1484 includes generating, a sensed signal via the at least onedrive-sense circuit, wherein the at least one drive-sense circuitincludes: a first conversion circuit configured to convert, a receivesignal component of a sensor signal corresponding to the at least onepixel sensor into the sensed signal, wherein the sensed signal indicatesa change in an electrical characteristic associated with the one of theplurality of pixel sensors; and a second conversion circuit configuredto generate, based on the sensed signal, a drive signal component of thesensor signal corresponding to the at least one pixel sensor. Step 1486includes generating image data based on the sensed signal. Step 1488includes transmitting the image data to an autonomous vehicle system ofthe autonomous vehicle.

It is noted that terminologies as may be used herein such as bit stream,stream, signal sequence, etc. (or their equivalents) have been usedinterchangeably to describe digital information whose contentcorresponds to any of a number of desired types (e.g., data, video,speech, text, graphics, audio, etc. any of which may generally bereferred to as ‘data’).

As may be used herein, the terms “substantially” and “approximately”provide an industry-accepted tolerance for its corresponding term and/orrelativity between items. For some industries, an industry-acceptedtolerance is less than one percent and, for other industries, theindustry-accepted tolerance is 10 percent or more. Other examples ofindustry-accepted tolerance range from less than one percent to fiftypercent. Industry-accepted tolerances correspond to, but are not limitedto, component values, integrated circuit process variations, temperaturevariations, rise and fall times, thermal noise, dimensions, signalingerrors, dropped packets, temperatures, pressures, material compositions,and/or performance metrics. Within an industry, tolerance variances ofaccepted tolerances may be more or less than a percentage level (e.g.,dimension tolerance of less than +/−1%). Some relativity between itemsmay range from a difference of less than a percentage level to a fewpercent. Other relativity between items may range from a difference of afew percent to magnitude of differences.

As may also be used herein, the term(s) “configured to”, “operablycoupled to”, “coupled to”, and/or “coupling” includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for an example of indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.

As may even further be used herein, the term “configured to”, “operableto”, “coupled to”, or “operably coupled to” indicates that an itemincludes one or more of power connections, input(s), output(s), etc., toperform, when activated, one or more its corresponding functions and mayfurther include inferred coupling to one or more other items. As maystill further be used herein, the term “associated with”, includesdirect and/or indirect coupling of separate items and/or one item beingembedded within another item.

As may be used herein, the term “compares favorably”, indicates that acomparison between two or more items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1. As maybe used herein, the term “compares unfavorably”, indicates that acomparison between two or more items, signals, etc., fails to providethe desired relationship.

As may be used herein, one or more claims may include, in a specificform of this generic form, the phrase “at least one of a, b, and c” orof this generic form “at least one of a, b, or c”, with more or lesselements than “a”, “b”, and “c”. In either phrasing, the phrases are tobe interpreted identically. In particular, “at least one of a, b, and c”is equivalent to “at least one of a, b, or c” and shall mean a, b,and/or c. As an example, it means: “a” only, “b” only, “c” only, “a” and“b”, “a” and “c”, “b” and “c”, and/or “a”, “b”, and “c”.

As may also be used herein, the terms “processing module”, “processingcircuit”, “processor”, “processing circuitry”, and/or “processing unit”may be a single processing device or a plurality of processing devices.Such a processing device may be a microprocessor, micro-controller,digital signal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, processing circuitry, and/or processing unitmay be, or further include, memory and/or an integrated memory element,which may be a single memory device, a plurality of memory devices,and/or embedded circuitry of another processing module, module,processing circuit, processing circuitry, and/or processing unit. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, cache memory, and/or any device that stores digital information.Note that if the processing module, module, processing circuit,processing circuitry, and/or processing unit includes more than oneprocessing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,processing circuitry and/or processing unit implements one or more ofits functions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory and/or memory element storing thecorresponding operational instructions may be embedded within, orexternal to, the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry. Still further notethat, the memory element may store, and the processing module, module,processing circuit, processing circuitry and/or processing unitexecutes, hard coded and/or operational instructions corresponding to atleast some of the steps and/or functions illustrated in one or more ofthe Figures. Such a memory device or memory element can be included inan article of manufacture.

One or more examples have been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claims. Further, the boundariesof these functional building blocks have been arbitrarily defined forconvenience of description. Alternate boundaries could be defined aslong as the certain significant functions are appropriately performed.Similarly, flow diagram blocks may also have been arbitrarily definedherein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence couldhave been defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claims. One of average skill in the art will alsorecognize that the functional building blocks, and other illustrativeblocks, modules and components herein, can be implemented as illustratedor by discrete components, application specific integrated circuits,processors executing appropriate software and the like or anycombination thereof.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with one or more other routines. In addition, a flow diagrammay include an “end” and/or “continue” indication. The “end” and/or“continue” indications reflect that the steps presented can end asdescribed and shown or optionally be incorporated in or otherwise usedin conjunction with one or more other routines. In this context, “start”indicates the beginning of the first step presented and may be precededby other activities not specifically shown. Further, the “continue”indication reflects that the steps presented may be performed multipletimes and/or may be succeeded by other activities not specificallyshown. Further, while a flow diagram indicates a particular ordering ofsteps, other orderings are likewise possible provided that theprinciples of causality are maintained.

The one or more examples are used herein to illustrate one or moreaspects, one or more features, one or more concepts, and/or one or moreexamples. A physical example of an apparatus, an article of manufacture,a machine, and/or of a process may include one or more of the aspects,features, concepts, examples, etc. described with reference to one ormore of the examples discussed herein. Further, from figure to figure,the examples may incorporate the same or similarly named functions,steps, modules, etc. that may use the same or different referencenumbers and, as such, the functions, steps, modules, etc. may be thesame or similar functions, steps, modules, etc. or different ones.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of theexamples. A module implements one or more functions via a device such asa processor or other processing device or other hardware that mayinclude or operate in association with a memory that stores operationalinstructions. A module may operate independently and/or in conjunctionwith software and/or firmware. As also used herein, a module may containone or more sub-modules, each of which may be one or more modules.

As may further be used herein, a computer readable memory includes oneor more memory elements. A memory element may be a separate memorydevice, multiple memory devices, or a set of memory locations within amemory device. Such a memory device may be a read-only memory, randomaccess memory, volatile memory, non-volatile memory, static memory,dynamic memory, flash memory, cache memory, a quantum register or otherquantum memory and/or any other device that stores data in anon-transitory manner. Furthermore, the memory device may be in a formof a solid-state memory, a hard drive memory or other disk storage,cloud memory, thumb drive, server memory, computing device memory,and/or other non-transitory medium for storing data. The storage of dataincludes temporary storage (i.e., data is lost when power is removedfrom the memory element) and/or persistent storage (i.e., data isretained when power is removed from the memory element).

As used herein, a transitory medium shall mean one or more of: (a) awired or wireless medium for the transportation of data as a signal fromone computing device to another computing device for temporary storageor persistent storage; (b) a wired or wireless medium for thetransportation of data as a signal within a computing device from oneelement of the computing device to another element of the computingdevice for temporary storage or persistent storage; (c) a wired orwireless medium for the transportation of data as a signal from onecomputing device to another computing device for processing the data bythe other computing device; and (d) a wired or wireless medium for thetransportation of data as a signal within a computing device from oneelement of the computing device to another element of the computingdevice for processing the data by the other element of the computingdevice. As may be used herein, a non-transitory computer readable memoryis substantially equivalent to a computer readable memory. Anon-transitory computer readable memory can also be referred to as anon-transitory computer readable storage medium.

While particular combinations of various functions and features of theone or more examples have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent disclosure is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A method for use in an imaging device, the methodcomprising: (a) providing a plurality of pixel sensors arranged in afirst direction and a second direction that respond to incident light,wherein the first direction is different than the second direction; (b)providing a plurality drive-sense circuits, wherein each of theplurality of drive-sense circuits is coupled to a corresponding one ofthe plurality of pixel sensors; (c) generating a plurality of sensedsignals via the plurality of drive-sense circuits, wherein each of theplurality of drive-sense circuits includes: a first conversion circuitconfigured to convert a receive signal component of a sensor signalcorresponding to one of the plurality of pixel sensors, into acorresponding one of the plurality of sensed signals, wherein thecorresponding one of the plurality of sensed signals indicates a changein a capacitance associated with the corresponding one of the pluralityof pixel sensors; and a second conversion circuit configured togenerate, based on the corresponding one of the plurality of sensedsignals, a drive signal component of the sensor signal corresponding tothe one of the plurality of pixel sensors; and (d) generating image databased on the plurality of sensed signals.
 2. The method of claim 1,wherein the plurality of pixel sensors each include a CMOS circuithaving a photodiode.
 3. The method of claim 1, wherein the firstconversion circuit is configured to convert, based on an analogreference signal, the receive signal component of the sensor signalcorresponding to the one of the plurality of pixel sensors into thesensed signal; and wherein the analog reference signal is generatedbased on nominal reference data that indicates an electricalcharacteristic of the one of the plurality of pixel sensors in anabsence of the incident light.
 4. The method of claim 3, wherein thenominal reference data used by the first conversion circuit to generatethe sensed signal is also used by the first conversion circuit togenerate other sensed signals corresponding to other ones of theplurality of pixel sensors.
 5. The method of claim 3, wherein thenominal reference data is customized to the one of the plurality ofpixel sensors.
 6. The method of claim 3, wherein the first conversioncircuit generates other sensed signals corresponding to other ones ofthe plurality of pixel sensors, based on a plurality of other nominalreference data customized to the other ones of the plurality of pixelsensors.
 7. The method of claim 3, wherein the electrical characteristicindicates a capacitance of the one of the plurality of pixel sensors inan absence of the incident light.
 8. The method of claim 1, wherein thefirst direction corresponds to a row direction of an array and thesecond direction corresponds to a column direction of the array.
 9. Themethod of claim 8, wherein the plurality drive-sense circuits arecoupled to pixel sensors arranged in the row direction.
 10. The methodof claim 8, wherein the plurality drive-sense circuits are coupled topixel sensors arranged in the column direction.
 11. An imaging devicecomprising: a plurality of pixel sensors arranged in a first directionand a second direction that respond to incident light, wherein the firstdirection is different than the second direction; a plurality ofdrive-sense circuits configured to generate a plurality of sensedsignals, wherein each of the plurality of drive-sense circuits includes:a first conversion circuit configured to convert a receive signalcomponent of a sensor signal corresponding to one of the plurality ofpixel sensors, into a corresponding one of the plurality of sensedsignals, wherein the corresponding one of the plurality of sensedsignals indicates a change in a capacitance associated with thecorresponding one of the plurality of pixel sensors; and a secondconversion circuit configured to generate, based on the correspondingone of the plurality of sensed signals, a drive signal component of thesensor signal corresponding to the one of the plurality of pixelsensors; wherein a graphics processing module is configured to generateimage data based on the plurality of sensed signals.
 12. The imagingdevice of claim 11 wherein the plurality of pixel sensors each include aCMOS circuit having a photodiode.
 13. The imaging device of claim 11wherein the first conversion circuit is configured to convert, based onan analog reference signal, the receive signal component of the sensorsignal corresponding to the one of the plurality of pixel sensors intothe sensed signal; and wherein the analog reference signal is generatedbased on nominal reference data that indicates an electricalcharacteristic of the one of the plurality of pixel sensors in anabsence of the incident light.
 14. The imaging device of claim 13wherein the nominal reference data used by the first conversion circuitto generate the sensed signal is also used by the first conversioncircuit to generate other sensed signals corresponding to other ones ofthe plurality of pixel sensors.
 15. The imaging device of claim 13wherein the nominal reference data is customized to the one of theplurality of pixel sensors.
 16. The imaging device of claim 13 whereinthe first conversion circuit generates other sensed signalscorresponding to other ones of the plurality of pixel sensors, based ona plurality of other nominal reference data customized to the other onesof the plurality of pixel sensors.
 17. The imaging device of claim 13wherein the electrical characteristic indicates a capacitance of the oneof the plurality of pixel sensors in an absence of the incident light.18. The imaging device of claim 11, wherein the first directioncorresponds to a row direction of an array and the second directioncorrespond to a column direction of the array.
 19. The imaging device ofclaim 18, wherein the plurality drive-sense circuits are coupled topixel sensors arranged in the row direction.
 20. The imaging device ofclaim 18, wherein the plurality drive-sense circuits are coupled topixel sensors arranged in the column direction.